Mixed solvent composition

ABSTRACT

A mixed solvent composition, for cleaning electronic components, which consists essentially of dichloropentafluoropropane and 1,1,1,2,3,4,4,5,5,5-decafluoropentane.

The present invention relates to mixed solvent compositions used as cleaning agents for electronic components including a printed circuit board and an IC, precision machinery parts, glass substrates, or the like.

Abbreviations and terms used in the present specification are illustrated below.

R113: 1,1,2-trichloro-1,2,2-trifluoroethane

R225: a mixture of one or two or more of dichloropentafluoropropane having the molecular formula C₃ HCl₂ F₅

R225ca: 3,3-dichloro-1,1,1,2,2-pentafluoropropane

R225cb: 1,3-dichloro-1,1,2,2,3-pentafluoropropane

R225mix: a mixture of at least two dichloropentafluoropropane isomers selected from the group consisting of R225ca, R225cb and other dichloropentafluoropropane isomers

R43-10mee: 1,1,1,2,3,4,4,5,5,5-decafluoropentane

R51-14M: a mixture of one or two or more of perfluorohexane having the molecular formula C₆ F₁₄

R51-14: perfluoro (n-hexane)

R51-14my: perfluoro (4-methylpentane)

R51-14mcy: pefluoro (3-methylpentane)

R51-14mix: a mixture of at least two perfluorohexane isomers selected from the group consisting of R51-14, R51-14my, R51-14mcy and other perfluorohexane isomers

Azeotropic mixed solvent composition: a mixed solvent composition, the composition of which does not substantially vary even by repeating distillation-condensation operations

Azeotropic-like mixed solvent composition: a mixed solvent composition, the composition of which varies only within the range of ±2% even by repeating distillation-condensation operations

BACKGROUND ART

To remove various oils, greases, fluxes and the like, R113 which is nonflammable, low toxic and excellent in stability, or a mixed solvent composition comprising R113 and a solvent miscible with R113 is widely used. Since R113 has such characteristics that it does not have an adverse effect on a base material such as a metal, a plastic or an elastomer and selectively dissolves various soils, it has been suitable for cleaning various electronic components, precision machinery parts, optical components or the like, made of a metal, a plastic, an elastomer or the like. Also, U.S. Pat. No. 5,304,322 discloses a cleaning agent for aircrafts, which comprises a C₄ -C₈ perfluorocarbon, a C₂ -C₅ hydrochlorofluorocarbon and a C₅ -C₉ petroleum distillate. In spite of various advantages of conventionally used R113, its production and consumption are regulated, because it has such a long life time in the troposphere by virtue of its chemical stability that it can diffuse to the stratosphere, where it is decomposed by an ultraviolet ray, producing chlorine radicals and the chlorine radicals cause a chain reaction with stratospheric ozone to deplete the ozone layer.

For this reason, alternative solvents to R113, which do not cause depletion of the ozone layer are widely being researched.

An object of the present invention is to provide a novel mixed solvent composition which satisfies the excellent properties of conventional R113 and can be used as an alternative solvent which does not substantially affect the ozone layer.

DISCLOSURE OF INVENTION

The present invention has been made to accomplish the above object, and provides a mixed solvent composition which comprises R225 and at least one component selected from the group consisting of R43-10mee and R51-14M, as the essential components, and a mixed solvent composition which comprises R225, an alcohol and at least one component selected from the group consisting of R43-10mee and R51-14M. In the following description including Examples, "%" means "% by weight".

In the mixed solvent composition comprising R225 and at least one of R43-10mee and R51-14M, as the essential components, the proportion of each of R43-10mee and R51-14M is preferably from 10 to 1,000 parts by weight to 100 parts by weight of R225. More preferable examples include the following azeotropic or azeotropic-like mixed solvent compositions (1) to (13).

(1) An azeotropic-like mixed solvent composition comprising from 40 to 55% of R43-10mee and from 45 to 60% of R225ca.

(2) An azeotropic mixed solvent composition comprising 48% of R43-10mee and 52% of R225ca.

(3) An azeotropic-like mixed solvent composition comprising from 50 to 70% of R43-10mee and from 30 to 50% of R225cb.

(4) An azeotropic mixed solvent composition comprising 58% of R43-10mee and 42% of R225cb.

(5) An azeotropic-like mixed solvent composition comprising from 10 to 50% of R225mix and from 50 to 90% of R43-10mee.

(6) An azeotropic-like mixed solvent composition comprising from 30 to 75% of R225ca and from 25 to 70% of R51-14mix comprising R51-14 as the main component.

(7) An azeotropic-like mixed solvent composition comprising from 30 to 75% of R225ca and from 25 to 70% of R51-14.

(8) An azeotropic mixed solvent composition comprising 55% of R225ca and 45% of R51-14.

(9) An azeotropic-like mixed solvent composition comprising from 25 to 60% of R225cb and from 40 to 75% of R51-14mix comprising R51-14 as the main component.

(10) An azeotropic-like mixed solvent composition comprising from 25 to 60% of R225cb and from 40 to 75% of R51-14.

(11) An azeotropic mixed solvent composition comprising 45% of R225cb and 55% of R51-14.

(12) An azeotropic-like mixed solvent composition comprising from 25 to 70% of R225mix and from 30 to 75% of R51-14mix comprising R51-14 as the main component.

(13) An azeotropic-like mixed solvent composition comprising from 25 to 70% of R225mix and from 30 to 75% of R51-14.

The present invention further provides a mixed solvent composition comprising R225, an alcohol and at least one component selected from the group consisting of R43-10mee and R51-14M, as the essential components. Preferably, in this composition, the proportion of R43-10mee is from 10 to 1000 parts by weight, the proportion of R51-14M is from 30 to 500 parts by weight and the proportion of an alcohol is from 1 to 100 parts by weight, to 100 parts by weight of R225. More preferable examples include the following azeotropic or azeotropic-like mixed solvent compositions (14) to (16).

(14) an azeotropic-like mixed solvent composition comprising from 20 to 50% of R225mix, from 45 to 75% of R51-14M and from 3 to 10% of methanol.

(15) An azeotropic-like mixed solvent composition comprising from 20 to 45% of R225mix, from 47 to 75% of R51-14M and from 3 to 8% of ethanol.

(16) An azeotropic-like mixed solvent composition comprising from 20 to 60% of R225mix, from 38.5 to 75% of R51-14M and from 1.5 to 7% of 2-propanol.

In addition to the above-mentioned methanol, ethanol and 2-propanol, preferable other examples of an alcohol include 1-propanol, 1-butanol, 2-butanol, isobutanol, t-butanol and the like.

Preferable examples of R225 include R225ca or R225cb respectively alone or a mixture of R225ca and R225cb. The mixture of R225ca and R225cb is preferably a mixture of from 0.01 to 99.99% of R225ca and from 0.01 to 99.99% of R225cb, more preferably a mixture of from 1 to 99% of R225ca and from 1 to 99% of R225cb. The mixture of R225ca and R225cb exhibits azeotropic-like action in a wide composition range. A preferable example of R225mix include a mixture of R225ca and R225cb.

R51-14M is preferably R51-14, R51-14my or R51-14mcy respectively alone or a mixture of at least one of these compounds. When R51-14M is a mixture, such a mixture should preferably comprise R51-14 as the main component. A preferable mixture example of R51-14M is a mixture comprising from 65 to 77% of R51-14, from 16 to 26% of R51-14my and from 2 to 12% of R51-14mcy, more preferably a mixture comprising from 70 to 75% of R51-14, from 18 to 22% of R51-14my and from 5 to 10% of R51-14mcy.

In order to improve mainly a dissolving property, the mixed solvent composition of the present invention may contain one or two or more compounds selected from the following compounds in an amount of from 0.1 to 50%, preferably from 0.1 to 30%, more preferably from 0.1 to 20%:

hydrocarbons such as n-pentane, 2-methylbutane, 2,2-dimethylpropane, n-hexane, 3-methylpentane, 2,2-dimethylbutane, 2,3-dimethylbutane, n-heptane, 2-methylhexane, 3-methylhexane, 2,3-dimethylpentane, 2,4-dimethylpentane, n-octane, 2,2,3-trimethylpentane, 2,2,4-trimethylpentane, cyclopentane, cyclohexane, methylcyclohexane and ethylcyclohexane;

chlorinated hydrocarbons such as dichloromethane, cis-1,2-dichloroethylene, trans-1,2-dichloroethylene, trichloroethylene and tetrachloroethylene;

ketones such as acetone, methyl ethyl ketone, methyl butyl ketone and methyl isobutyl ketone;

ethers such as diethyl ether, methyl cellosolve, tetrahydrofuran and 1,4-dioxane;

chlorofluorohydrocarbons such as 2,2-dichloro-1,1,1-trifluoroethane and 1,1-dichloro-1-fluoroethane; and

esters such as methyl acetate, ethyl acetate, propyl acetate and butyl acetate.

In order to improve mainly a stability, the mixed solvent composition of the present invention may contain one or two or more compounds selected from the following compounds in an amount of from 0.001 to 10%, preferably from 0.001 to 5%:

nitro compounds such as nitromethane, nitroethane, nitropropane and nitrobenzene;

amines such as diethylamine, triethylamine, i-propylamine, n-butylamine and i-butylamine;

phenols such as phenol, o-cresol, m-cresol, p-cresol, thymol, p-t-butylphenol, t-butylcatechol, catechol, isoeugenol, o-methoxyphenol, bisphenol A, isoamyl salicylate, benzyl salicylate, methyl salicylate and 2,6-di-t-butyl-p-cresol; and

triazoles such as 2-(2'-hydroxy-5'-methyl-phenyl)benzotriazole, 2-(2'-hydroxy-3'-t-buthyl-5'-methylphenyl)-5-chlorobenzotriazole, 1,2,3-benzotriazole and 1- (N,N-bis-2-ethylhexyl)aminomethyl!benzotriazole.

The mixed solvent composition of the present invention has a dissolving power at the same degree as a conventional R113 type solvent, and can be used suitably in various ways. Specifically, it is used as a paint solvent, an extractant, or a cleaning agent for removing grease, oil, wax, ink or the like. Also, it is used as a cleaning agent or a dust-removing agent for glass, ceramic, plastic, elastomer, rubber, metal or other various articles. More specifically, it is used suitably as a cleaning agent or a dust-removing agent for ICs, electric devices, precision machines, optical lenses or the like.

As a cleaning method, various methods including manual wiping, immersing, spraying, vibrating, supersonic cleaning, vapor degreasing or a combination of these methods, may be used.

The mixed solvent composition of the present invention provides the excellent properties of conventional R113 and also provides an advantage that it does not substantially affect the ozone layer.

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention is further illustrated by the following Examples.

Evaluation was conducted by the following three methods.

(1) A test coupon (25 mm×30 mm×2 mm) made of SUS-304 was dipped in a machine oil (CQ-30, manufactured by Nippon Petrochemicals Co., Ltd.) and then immersed in the mixed solvent compositions of the present invention as identified in Tables for 5 minutes. Thereafter, the degree of removal of the machine oil was evaluated. The results are shown with evaluation standards for the degree of removal A such that ⊚: excellently removed, Δ: slightly remained and X: substantially remained.

(2) Flux (speedy flux AGF-J-I: manufactured by Asahi Kagaku Kenkyusho) was coated on the entire surface of a printed circuit board (50 mm×100 mm×1.6 mm) made of epoxy-glass, and soldering was carried out at a soldering temperature of 260° C. by means of a wave soldering machine. Then, defluxing was carried out by immersing it in the compositions of the present invention as identified in Tables for 3 minutes, and the degree of removal of the flux was evaluated. The results are shown with evaluation standards for the degree of removal B such that ⊚: excellently removed, Δ: slightly remained and X: substantially remained.

(3) A glass plate of 30 mm×18 mm×5 mm in size was dipped in pure water and then immersed in the compositions of the present invention shown in Tables for 20 seconds to be dewatered. The glass plate was taken out and immersed in anhydrous methanol, and the degree of removal of deposited water was evaluated from the increase of water in the methanol. The results are shown with evaluation standards for the degree of removal C such that ⊚: excellently removed, Δ: slightly remained and X: substantially remained.

EXAMPLE 1

1,000 g of a mixed solvent composition consisting of 48% of R43-10mee (b.p. 53.6° C.) and 52% of R225ca (b.p. 51.1° C.) was charged into a distillation flask, and the flask was connected to a distillation column having a number of theoretical plates of 5. Then, the composition was heated and refluxed for 2 hours. After the composition reached equilibrium, the fraction was periodically collected and analyzed by gas chromatography. The results are shown in Table 1.

                  TABLE 1                                                          ______________________________________                                         Portion of                                                                     fraction                                                                       collected      Composition (%)                                                 (%)            R43-10mee R225ca                                                ______________________________________                                         20             48.0      52.0                                                  40             48.0      52.0                                                  60             48.0      52.0                                                  ______________________________________                                    

EXAMPLE 2

20 kg of mixed solvent composition consisting of 55% of R43-10mee and 45% of R225ca was charged into a small degreaser with one-sump, and the degreaser was operated for 6 hours per day for 3 days. Samples were periodically taken from the cleaning sump and the water separator and analyzed by gas chromatography. The results are shown in Table 2.

                  TABLE 2                                                          ______________________________________                                                Composition (%)                                                                Cleaning sump     Water separator                                       Time     R43-10mee R225ca    R43-10mee                                                                              R225ca                                    ______________________________________                                         After 6  55.0      45.0      55.0    45.0                                      hours                                                                          After 12 55.1      44.9      55.0    45.0                                      hours                                                                          After 18 55.1      44.9      54.9    45.1                                      hours                                                                          ______________________________________                                    

EXAMPLE 3

The same procedure as in Example 2 was repeated, except that 20 kg of a mixed solvent composition consisting of 40% of R43-10mee and 60% of R225ca was used as a mixed solvent composition. The results are shown in Table 3.

                  TABLE 3                                                          ______________________________________                                                Composition (%)                                                                Cleaning sump     Water separator                                       Time     R43-10mee R225ca    R43-10mee                                                                              R225ca                                    ______________________________________                                         After 6  40.0      60.0      40.0    60.0                                      hours                                                                          After 12 39.9      60.1      40.1    59.9                                      hours                                                                          After 18 39.9      60.1      40.1    59.9                                      hours                                                                          ______________________________________                                    

EXAMPLE 4

The same procedure as in Example 1 was repeated, except that 1,000 g of a mixed solvent composition consisting of 58% of R43-10mee and 42% of R225cb (b.p. 56.1° C.) was used as a mixed solvent composition. The shown in Table 4.

                  TABLE 4                                                          ______________________________________                                         Portion of                                                                     fraction                                                                       collected      Composition (%)                                                 (%)            R43-10mee R225cb                                                ______________________________________                                         20             58.0      42.0                                                  40             58.0      42.0                                                  60             58.0      42.0                                                  ______________________________________                                    

EXAMPLE 5

The same procedure as in Example 2 was repeated, except that 20 kg of a mixed solvent composition consisting of 70% of R43-10mee and 30% of R225cb was used as a mixed solvent composition. The results are shown in Table 5.

                  TABLE 5                                                          ______________________________________                                                Composition (%)                                                                Cleaning sump     Water separator                                       Time     R43-10mee R225cb    R43-10mee                                                                              R225cb                                    ______________________________________                                         After 6  70.0      30.0      70.0    30.0                                      hours                                                                          After 12 70.1      29.9      70.0    30.0                                      hours                                                                          After 18 70.1      29.9      69.9    30.1                                      hours                                                                          ______________________________________                                    

EXAMPLE 6

The same procedure as in Example 2 was repeated, except that 20 kg of a mixed solvent composition consisting of 50% of R43-10mee and 50% of R225cb was used as a mixed solvent composition. The results are shown in Table 6.

                  TABLE 6                                                          ______________________________________                                                Composition (%)                                                                Cleaning sump     Water separator                                       Time     R43-10mee R225cb    R43-10mee                                                                              R225cb                                    ______________________________________                                         After 6  50.0      50.0      50.0    50.0                                      hours                                                                          After 12 49.9      50.1      50.1    49.9                                      hours                                                                          After 18 49.9      50.1      50.1    49.9                                      hours                                                                          ______________________________________                                    

EXAMPLE 7

The same procedure as in Example 2 was repeated, except that 20 kg of a mixed solvent composition consisting of 90% of R43-10mee and 10% of R225mix (R225ca/R225cb=45%/55% mixture) was used as a mixed solvent composition. The results are shown in Table 7.

                  TABLE 7                                                          ______________________________________                                         Composition (%)                                                                Cleaning sump       Water separator                                            Time   R43-10mee  R225mix   R43-10mee                                                                               R225mix                                   ______________________________________                                         After 6                                                                               90.0       10.0      90.0     10.0                                      hours                                                                          After 12                                                                              90.1       9.9       89.9     10.1                                      hours                                                                          After 18                                                                              90.1       9.9       89.9     10.1                                      hours                                                                          ______________________________________                                    

EXAMPLE 8

The same procedure as in Example 2 was repeated, except that a mixed solvent composition consisting of 50% R43-10mee and 50% of R225mix (R225ca/R225cb=45%/55% mixture) was used as a mixed solvent composition. The results are shown in Table 8.

                  TABLE 8                                                          ______________________________________                                         Composition (%)                                                                Cleaning sump       Water separator                                            Time   R43-10mee  R225mix   R43-10mee                                                                               R225mix                                   ______________________________________                                         After 6                                                                               50.0       50.0      50.0     50.0                                      hours                                                                          After 12                                                                              50.0       50.0      50.0     50.0                                      hours                                                                          After 18                                                                              49.9       50.1      50.1     49.9                                      hours                                                                          ______________________________________                                    

EXAMPLES 9 to 16

By using the mixed solvent compositions shown in Table 9, a machine oil cleaning test (A) was carried out.

                  TABLE 9                                                          ______________________________________                                                                        Degree of                                       No     Solvent composition                                                                              %     removal A                                       ______________________________________                                          9     R43-10mee         55    ⊚                                       R225ca            45                                                    10     R43-10mee         48    ⊚                                       R225ca            52                                                    11     R43-10mee         40    ⊚                                       R225ca            60                                                    12     R43-10mee         70    ⊚                                       R225cb            30                                                    13     R43-10mee         58    ⊚                                       R225cb            42                                                    14     R43-10mee         50    ⊚                                       R225cb            50                                                    15     R43-10mee         90    ⊚                                       R225ca             4                                                           R225cb             6                                                    16     R43-10mee         50    ⊚                                       R225ca            10                                                           R225cb            40                                                    ______________________________________                                    

EXAMPLE 17 to 24

By using the mixed solvent compositions shown in Tables 10 and 11, a defluxing test (B) was carried out.

                  TABLE 10                                                         ______________________________________                                                                        Degree of                                       No     Solvent composition                                                                              %     removal B                                       ______________________________________                                         17     R43-10mee         50    ⊚                                       R225ca            40                                                           2-propanol        10                                                    18     R43-10mee         45    ⊚                                       R225ca            50                                                           methanol           5                                                    19     R43-10mee         36    ⊚                                       R225ca            56                                                           ethanol            8                                                    20     R43-10mee         60    ⊚                                       R225cb            30                                                           methanol          10                                                    ______________________________________                                    

                  TABLE 11                                                         ______________________________________                                                                        Degree of                                       No     Solvent composition                                                                              %     removal B                                       ______________________________________                                         21     R43-10mee         55    ⊚                                       R225cb            40                                                           2-propanol         5                                                    22     R43-10mee         47    ⊚                                       R225cb            47                                                           ethanol            6                                                    23     R43-10mee         80    ⊚                                       R225ca             4                                                           R225cb             6                                                           methanol          10                                                    24     R43-10mee         50    ⊚                                       R225ca            20                                                           R225cb            25                                                           2-propanol         5                                                    ______________________________________                                    

EXAMPLE 25 to 32

By using the mixed solvent compositions shown in Tables 12 and 13, a test (C) for removing deposited water was carried out.

                  TABLE 12                                                         ______________________________________                                                                        Degree of                                       No     Solvent composition                                                                              %     removal C                                       ______________________________________                                         25     R43-10mee         53    ⊚                                       R225ca            42                                                           2-propanol         5                                                    26     R43-10mee         40    ⊚                                       R225ca            50                                                           ethanol           10                                                    27     R43-10mee         35    ⊚                                       R225ca            50                                                           methanol          15                                                    28     R43-10mee         62    ⊚                                       R225cb            33                                                           methanol           5                                                    ______________________________________                                    

                  TABLE 13                                                         ______________________________________                                                                        Degree of                                       No       Solvent composition                                                                            %     removal C.                                      ______________________________________                                         29       R43-10mee       55    ⊚                                         R225cb          35                                                             ethanol         10                                                    30       R43-10mee       46    ⊚                                         R225cb          46                                                             2-propanol      8                                                     31       R43-10mee       85    ⊚                                         R225ca          5                                                              R225cb          2                                                              ethanol         8                                                     32       R43-10mee       45    ⊚                                         R225ca          10                                                             R225cb          35                                                             methanol        10                                                    ______________________________________                                    

EXAMPLE 33

250 cc of a mixed solvent composition of R225ca (b.p. 51.1° C.) and R51-14 (b.p. 56° C.) in such a ratio as shown in Table 14 was charged into an Othmer type gas-liquid equilibrium distillation apparatus, and was heated. After the composition reached equilibrium, samples were taken from the gas phase and the liquid phase and were analyzed by gas chromatography. The results are shown in Table 14. The azeotropic composition was R225ca/R51-14=55.0%/45.0%.

                  TABLE 14                                                         ______________________________________                                         Example 33:        Example 33:                                                 Gas phase          Liquid phase                                                composition (%)    composition (%)                                             R225ca   R51-14        R225ca  R51-14                                          ______________________________________                                         90.0     10.0          94.0    6.0                                             75.0     25.0          79.0    21.0                                            55.0     45.0          55.0    45.0                                            43.0     57.0          40.0    60.0                                            30.0     70.0          25.0    75.0                                            14.0     86.0          10.0    90.0                                            ______________________________________                                    

EXAMPLE 34

1,000 g of a mixed solvent composition of R225ca/R51-14=30.0%/70.0% was charged into a distillation flask, and the flask was connected to a distillation column having a number of theoretical plates of 5. Then, the composition was heated and fluxed for 2 hours. After the composition reached equilibrium, the fraction was periodically collected and analyzed by gas chromatography. The results are shown in Table 15.

EXAMPLE 35

The same procedure as in Example 34 was repeated, except that 1,000 g of a mixed solvent composition of R225ca/R51-14=75.0%/25.0% was used as a mixed solvent composition. The results as shown in Table 15.

                  TABLE 15                                                         ______________________________________                                         Portion of                                                                     fraction  Example 34:     Example 35:                                          collected Composition (%) Composition (%)                                      (%)       R225ca  R51-14      R225ca                                                                               R51-14                                     ______________________________________                                         20        30.0    70.0        75.0  25.0                                       60        30.0    70.0        75.0  25.0                                       80        30.1    69.9        74.9  25.1                                       ______________________________________                                    

EXAMPLE 36

The same procedure as in Example 34 was repeated, except that 1,000 g of a mixed solvent composition of R225ca/R51-14/R51-14my/R51-14mcy=30.0%/50.0%/15.0%/5.0% was used as a mixed solvent composition. The results are shown in Table 16.

                  TABLE 16                                                         ______________________________________                                         Portion of                                                                     fraction  Example 36:                                                          collected Composition (%)                                                      (%)       R225ca  R51-14    R51-14my                                                                              R51-14mcy                                   ______________________________________                                         20        30.0    50.0      15.0   5.0                                         60        30.0    50.0      15.0   5.0                                         80        30.1    49.9      15.0   5.0                                         ______________________________________                                    

EXAMPLE 37

The same procedure as in Example 34 was repeated, except that 1,000 g of a mixed solvent composition of R225ca/R51-14/R51-14my/R51-14mcy=75.0%/18.0%/5.0%/2.0% was used as a mixed solvent composition. The results are shown in Table 17.

                  TABLE 17                                                         ______________________________________                                         Portion of                                                                     fraction  Example 37:                                                          collected Composition (%)                                                      (%)       R225ca  R51-14    R51-14my                                                                              R51-14mcy                                   ______________________________________                                         20        75.0    18.0      5.0    2.0                                         60        75.0    18.0      5.0    2.0                                         80        74.9    18.1      5.0    2.0                                         ______________________________________                                    

EXAMPLE 38

250 cc of a mixed solvent composition of R225cb (b.p. 56.1° C.) and R51-14 (b.p. 56° C.) in such a ratio as shown in Table 18 was charged into an Othmer type gas-liquid equilibrium distillation apparatus, and was heated. After the composition reached equilibrium, samples were taken from the gas phase and the liquid phase and were analyzed by gas chromatography. The results are shown in Table 18. The azeotropic composition was R225cb/R51-14=45.0%/55.0%.

                  TABLE 18                                                         ______________________________________                                         Example 38:        Example 38:                                                 Gas phase          Liquid phase                                                composition (%)    composition (%)                                             R225cb   R51-14        R225cb  R51-14                                          ______________________________________                                         20.0     80.0          11.0    89.0                                            32.0     68.0          23.0    77.0                                            42.0     58.0          41.0    59.0                                            45.0     55.0          45.0    55.0                                            56.0     44.0          61.0    39.0                                            80.0     20.0          87.0    13.0                                            ______________________________________                                    

EXAMPLE 39

The same procedure as in Example 34 was repeated, except that 1,000 g of a mixed solvent composition of R225cb/R51-14=25.0%/75.0% was used as a mixed solvent composition. The results are shown in Table 19.

EXAMPLE 40

The same procedure as in Example 34 was repeated, except that 1,000 g of a mixed solvent composition of R225cb/R51-14=60.0%/40.0% was used as a mixed solvent composition. The results are shown in Table 19.

                  TABLE 19                                                         ______________________________________                                         Portion of                                                                     fraction  Example 39:         Example 40:                                      collected Composition (%) Composition (%)                                      (%)       R225cb  R51-14      R225cb                                                                               R51-14                                     ______________________________________                                         20        25.0    75.0        60.0  40.0                                       60        25.0    75.0        60.0  40.0                                       80        25.1    74.9        59.9  40.1                                       ______________________________________                                    

EXAMPLE 41

The same procedure as in Example 34 was repeated, except that 1,000 g of a mixed solvent composition R225cb/R51-14/R51-14my/R51-14mcy=25.0%/47.0%/13.0%/5.0% was used as a mixed solvent composition. The results are shown in Table 20.

                  TABLE 20                                                         ______________________________________                                         Portion of                                                                     fraction  Example 41:                                                          collected Composition (%)                                                      (%)       R225cb  R51-14    R51-14my                                                                              R51-14mcy                                   ______________________________________                                         20        25.0    54.0      16.0   5.0                                         60        25.0    54.0      16.0   5.0                                         80        25.1    53.9      16.0   5.0                                         ______________________________________                                    

EXAMPLE 42

The same procedure as in Example 34 was repeated, except that 1,000 g of a mixed solvent composition of R225cb/R51-14/R51-14my/R51-14mcy=60.0%/29.0%/8.0%/3.0% was used as a mixed solvent composition. The results are shown in Table 21.

                  TABLE 21                                                         ______________________________________                                         Portion of                                                                     fraction  Example 42:                                                          collected Composition (%)                                                      (%)       R225cb  R51-14    R51-14my                                                                              R51-14mcy                                   ______________________________________                                         20        60.0    29.0      8.0    3.0                                         60        60.0    29.0      8.0    3.0                                         80        59.9    29.1      8.0    3.0                                         ______________________________________                                    

EXAMPLE 43

The same procedure as in Example 34 was repeated, except that 1,000 g of a mixed solvent composition consisting of 50.0% of R225 of R225ca/R225cb=45/55 (weight ratio) and 50.0% of R51-14 was used as a mixed solvent composition. The results are shown in Table 22.

EXAMPLE 44

The same procedure as in Example 34 was repeated, except that 1,000 g of a mixed solvent composition consisting of 25.0% of R225 of R225ca/R225cb=45/55 (weight ratio) and 75.0% of R51-14 was used as a mixed solvent composition. The results are shown in Table 22.

EXAMPLE 45

The same procedure as in Example 34 was repeated, except that 1,000 g of a mixed solvent composition consisting of 70.0% of R225mix of R225ca/R225cb=45/55 (weight ratio) and 30.0% of R51-14 was used as a mixed solvent composition. The results are shown in Table 22.

                  TABLE 22                                                         ______________________________________                                         Portion                                                                        of                                                                             fraction                                                                             Example 43:  Example 44:  Example 45:                                    collect-                                                                             Composition (%)                                                                             Composition (%)                                                                             Composition (%)                                ed (%)                                                                               R225mix  R51-14  R225mix                                                                               R51-14                                                                               R225mix                                                                               R51-14                              ______________________________________                                         20    51.0     49.0    25.0   75.0  70.0   30.0                                60    51.0     49.0    25.0   75.0  70.0   30.0                                80    51.2     48.8    25.1   74.9  69.9   30.1                                ______________________________________                                    

EXAMPLE 46

The same procedure as in Example 34 was repeated, except that 1,000 g of a mixed solvent composition consisting of 25.0% of R225mix of R225ca/R225cb=45/55 (weight ratio), 47.0% of R51-14, 13.0% of R51-14my and 5.0% of R51-14mcy was used as a mixed solvent composition. The results are shown in Table 23.

                  TABLE 23                                                         ______________________________________                                         Portion of                                                                     fraction  Example 46:                                                          collected Composition (%)                                                      (%)       R225mix  R51-14    R51-14my                                                                              R51-14mcy                                  ______________________________________                                         20        25.0     54.0      16.0   5.0                                        60        25.0     54.0      16.0   5.0                                        80        25.1     53.9      16.0   5.0                                        ______________________________________                                    

EXAMPLE 47

The same procedure as in Example 34 was repeated, except that 1,000 g of a mixed solvent composition consisting of 55.0% of R225mix of R225ca/R225cb=45/55 (weight ratio), 33.0% of R51-14, 9.0% of R51-14my and 3.0% of R51-14mcy was used as a mixed solvent composition. The results are shown in Table 24.

                  TABLE 24                                                         ______________________________________                                         Portion of                                                                     fraction  Example 47:                                                          collected Composition (%)                                                      (%)       R225mix  R51-14    R51-14my                                                                              R51-14mcy                                  ______________________________________                                         20        55.0     33.0      9.0    3.0                                        60        55.0     33.0      9.0    3.0                                        80        55.1     32.9      9.0    3.0                                        ______________________________________                                    

EXAMPLE 48

The same procedure as in Example 34 was repeated, except that 1,000 g of a mixed solvent composition consisting of 45.0% of R225mix of R225ca/R225cb=45/55 (weight ratio), 40.0% of R51-14, 11.0% of R51-14my and 4.0% of R51-14mcy was used as a mixed solvent composition. The results are shown in table 25.

                  TABLE 25                                                         ______________________________________                                         Portion of                                                                     fraction  Example 48:                                                          collected Composition (%)                                                      (%)       R225mix  R51-14    R51-14my                                                                              R51-14mcy                                  ______________________________________                                         20        45.0     40.0      11.0   4.0                                        60        45.0     40.0      11.0   4.0                                        80        44.9     40.1      11.0   4.0                                        ______________________________________                                    

EXAMPLE 49

The same procedure as in Example 34 was repeated, except that 1,000 g of a mixed solvent composition consisting of 70.0% of R225mix of R225ca/R225cb=45/55 (weight ratio), 22.0% of R51-14, 6.0% of R51-14my and 2.0% of R51-14mcy was used as a mixed solvent composition. The results are shown in table 26.

                  TABLE 26                                                         ______________________________________                                         Portion of                                                                              Example 49:                                                           fraction Composition (%)                                                       collected (%)                                                                           R225mix  R51-14    R51-14my                                                                              R51-14mcy                                   ______________________________________                                         20       70.0     22.0      6.0    2.0                                         60       70.0     22.0      6.0    2.0                                         80       69.9     22.1      6.0    2.0                                         ______________________________________                                    

EXAMPLE 50 to 60

By using the mixed solvent compositions shown in Table 27, a machine oil cleaning test (A) was carried out.

                  TABLE 27                                                         ______________________________________                                                     Solvent            Degree of                                       Example     Composition  %     removal A                                       ______________________________________                                         50          R225ca       30    ⊚                                            R51-14       50                                                                R51-14my     15                                                                R51-14mcy     5                                                    51          R225ca       40    ⊚                                            R51-14       60                                                    52          R225ca       55    ⊚                                            R51-14       45                                                    53          R225ca       75    ⊚                                            R51-14       18                                                                R51-14my      5                                                                R51-14mcy     2                                                    54          R225cb       25    ⊚                                            R51-14       54                                                                R51-14my     16                                                                R51-14mcy     5                                                    55          R225cb       50    ⊚                                            R51-14       50                                                    56          R225cb       45    ⊚                                            R51-14       55                                                    57          R225cb       60    ⊚                                            R51-14       29                                                                R51-14my      8                                                                R51-14mcy     3                                                    58          R225ca       10    ⊚                                            R225cb       15                                                                R51-14       54                                                                R51-14my     16                                                                R51-14mcy     5                                                    59          R225ca       25    ⊚                                            R225cb       25                                                                R51-14       50                                                    60          R225ca       40    ⊚                                            R225cb       30                                                                R51-14       22                                                                R51-14my      6                                                                R51-14mcy     2                                                    ______________________________________                                    

EXAMPLE 61 to 69

By using the mixed solvent compositions shown in Table 28 and 29, defluxing test (B) and a test (C) for removing deposited water were carried out.

                  TABLE 28                                                         ______________________________________                                                   Solvent            Degree of                                                                             Degree of                                  Example   Composition                                                                              %        removal B                                                                             removal C                                  ______________________________________                                         61        R225ca    25       ⊚                                                                      ⊚                                     R51-14    47                                                                   R51-14my  13                                                                   R51-14mcy  5                                                                   methanol  10                                                         62        R225ca    40       ⊚                                                                      ⊚                                     R51-14    50                                                                   ethanol   10                                                         63        R225ca    68       ⊚                                                                      ⊚                                     R51-14    20                                                                   R51-14my   5                                                                   R51-14mcy  2                                                                   2-propanol                                                                                5                                                         64        R225cb    25       ⊚                                                                      ⊚                                     R51-14    47                                                                   R51-14my  13                                                                   R51-14mcy  5                                                                   ethanol   10                                                         65        R225cb    40       ⊚                                                                      ⊚                                     R51-14    55                                                                   2-propanol                                                                                5                                                         ______________________________________                                    

                  TABLE 29                                                         ______________________________________                                                   Solvent            Degree of                                                                             Degree of                                  Example   Composition                                                                              %        removal B                                                                             removal C                                  ______________________________________                                         66        R225cb    50       ⊚                                                                      ⊚                                     R51-14    25                                                                   R51-14my   7                                                                   R51-14mcy  3                                                                   methanol  15                                                         67        R225ca    10       ⊚                                                                      ⊚                                     R225cb    45                                                                   R51-14    29                                                                   R51-14my   8                                                                   R51-14mcy  3                                                                   2-propanol                                                                                5                                                         68        R225ca    20       ⊚                                                                      ⊚                                     R225cb    20                                                                   R51-14    50                                                                   methanol  10                                                         69        R225ca     5       ⊚                                                                      ⊚                                     R225cb    25                                                                   R51-14    40                                                                   R51-14my  11                                                                   R51-14mcy  4                                                                   ethanol   15                                                         ______________________________________                                    

EXAMPLE 70

1,000 g of a mixed solvent composition consisting of 45% of R225mix (R225ca/R225cb=45%/55%), 45% of R51-14 and 10% of methanol (MeOH) was charged into a distillation flask, and the flask was connected to a distillation column having a number of theoretical plates of 5. Then, the composition was heated and refluxed for 2 hours. After the composition reached equilibrium, the fraction was periodically collected and analyzed by gas chromatography. The results are shown in Table 30.

EXAMPLE 71

The same procedure as in Example 70 was repeated, except that 1,000 g of a mixed solvent composition consisting of 35% of R225mix (R225ca/R225cb=45%/55%), 62% of R51-14 and 3% of MeOH was used as a mixed solvent composition. The results are shown in Table 30.

                  TABLE 30                                                         ______________________________________                                         Portion of                                                                     fraction                                                                              Example 70:      Example 71:                                            collected                                                                             Composition (%)  Composition (%)                                        (%)    R225mix  R51-14  MeOH  R225mix                                                                               R51-14                                                                               MeOH                                ______________________________________                                         20     45.0     45.0    10.0  35.0   62.0  3.0                                 40     45.0     45.0    10.0  35.0   62.0  3.0                                 60     45.1     44.9    10.0  34.9   62.1  3.0                                 ______________________________________                                    

EXAMPLE 72

The same procedure as in Example 70 was repeated, except that 1,000 g of a mixed solvent composition consisting of 40% of R225mix (R225ca/R225cb=45%/55%), 36% of R51-14, 10% of R51-14my, 4% of R51-14mcy and 10% of MeOH was used as a mixed solvent composition. The are shown in Table 31.

                  TABLE 31                                                         ______________________________________                                         Portion of                                                                             Example 72:                                                            fraction                                                                               Composition (%)                                                        collected (%)                                                                          R225mix  R51-14  R51-14my                                                                               R51-14mcy                                                                              MeOH                                  ______________________________________                                         20      40.0     36.0    10.0    4.0     10.0                                  40      40.0     36.0    10.0    4.0     10.0                                  60      39.9     36.1    10.0    4.0     10.0                                  ______________________________________                                    

EXAMPLE 73

The same procedure as in Example 70 was repeated, except that 1,000 g of a mixed solvent composition consisting of 50% of R225mix (R225ca/R225cb=45%/55%), 34% of R51-14, 9% of R51-14my, 4% of R51-14mcy and 3% of MeOH was used as a mixed solvent composition. The results are shown in Table 32.

                  TABLE 32                                                         ______________________________________                                         Portion of                                                                             Example 73:                                                            fraction                                                                               Composition (%)                                                        collected (%)                                                                          R225mix  R51-14  R51-14my                                                                               R51-14mcy                                                                              MeOH                                  ______________________________________                                         20      50.0     34.0    9.0     4.0     3.0                                   40      50.0     34.0    9.0     4.0     3.0                                   60      50.1     33.9    9.0     4.0     3.0                                   ______________________________________                                    

EXAMPLE 74

The same procedure as in Example 70 was repeated, except that 1,000 g of a mixed solvent composition consisting of 20% of R225mix (R225ca/R225cb=45%/55%), 75% R51-14 and 5% of MeOH was used as a mixed solvent composition. The results are shown in Table 33.

                  TABLE 33                                                         ______________________________________                                         Portion of                                                                               Example 74:                                                          fraction  Composition (%)                                                      collected (%)                                                                            R225mix       R51-14  MeOH                                           ______________________________________                                         20        20.0          75.0    5.0                                            40        20.0          75.0    5.0                                            60        19.9          75.1    5.0                                            ______________________________________                                    

EXAMPLE 75

The same procedure as in Example 70 was repeated, except that 1,000 g of a mixed solvent composition consisting of 45% of R225mix (R225ca/R225cb=45%/55%), 47% of R51-14 and 8% of ethanol (EtOH) was used as a mixed solvent composition. The results are shown in Table 34.

EXAMPLE 76

The same procedure as in Example 70 was repeated, except that 1,000 g of a mixed solvent composition consisting of 28% of R225mix (R225ca/R225cb=45%/55%), 69% of R51-14 and 3% of EtOH was used as a mixed solvent composition. The results are shown in Table 34.

                  TABLE 34                                                         ______________________________________                                         Portion of                                                                             Example 75:      Example 76:                                           fraction                                                                               Composition (%)  Composition (%)                                       collected (%)                                                                          R225mix  R51-14  EtOH  R225mix                                                                               R51-14                                                                               EtOH                               ______________________________________                                         20      45.0     47.0    8.0   28.0   69.0  3.0                                40      45.0     47.0    8.0   28.0   69.0  3.0                                60      45.1     46.9    8.0   27.9   69.1  3.0                                ______________________________________                                    

EXAMPLE 77

The same procedure as in Example 70 was repeated, except that 1,000 g of a mixed solvent composition consisting of 30% of R225mix (R225ca/R225cb=45%/55%), 45% of R51-14, 12% of R51-14my, 5% of R51-14mcy and 8% of EtOH was used as a mixed solvent composition. The results are shown in Table 35.

                  TABLE 35                                                         ______________________________________                                         Portion of                                                                             Example 77:                                                            fraction                                                                               Composition (%)                                                        collected (%)                                                                          R225mix  R51-14   R51-14my                                                                              R51-14mcy                                                                               EtOH                                 ______________________________________                                         20      30.0     45.0     12.0   5.0      8.0                                  40      30.0     45.0     12.0   5.0      8.0                                  60      29.9     45.1     12.0   5.0      8.0                                  ______________________________________                                    

EXAMPLE 78

The same procedure as in Example 70 was repeated, except that 1,000 g of a mixed solvent composition consisting of 28% of R225mix (R225ca/R225cb=45%/55%), 50% of R51-14, 13% of R51-14my, 6% of R51-14mcy and 3% of EtOH was used as a mixed solvent composition. The results are shown in Table 36.

                  TABLE 36                                                         ______________________________________                                         Portion of                                                                             Example 78:                                                            fraction                                                                               Composition (%)                                                        collected (%)                                                                          R225mix  R51-14   R51-14my                                                                              R51-14mcy                                                                               EtOH                                 ______________________________________                                         20      28.0     50.0     13.0   6.0      3.0                                  40      28.0     50.0     13.0   6.0      3.0                                  60      27.9     50.1     13.0   6.0      3.0                                  ______________________________________                                    

EXAMPLE 79

The same procedure as in Example 70 was repeated, except that 1,000 g of a mixed solvent composition consisting of 20% of R225mix (R225ca/R225cb=45%/55%), 75% of R51-14 and 5% of EtOH was used as a mixed solvent composition. The results are shown in Table 37.

                  TABLE 37                                                         ______________________________________                                         Portion of Example 79:                                                         fraction   Composition (%)                                                     collected (%)                                                                             R225mix       R51-14  EtOH                                          ______________________________________                                         20         20.0          75.0    5.0                                           40         20.0          75.0    5.0                                           60         19.9          75.1    5.0                                           ______________________________________                                    

EXAMPLE 80

The same procedure as in Example 70 was repeated, except that 1,000 g of a mixed solvent composition consisting of 20% of R225mix (R225ca/R225cb=45%/55%), 73% of R51-14 and 7% of 2-propanol (2-PrOH) was used as a mixed solvent composition. The results are shown in Table 38.

EXAMPLE 81

The same procedure as in Example 70 was repeated, except that 1,000 g of a mixed solvent composition consisting of 60% of R225mix (R225ca/R225cb=45%/55%), 38.5% of R51-14 and 1.5% of 2-PrOH was used as a mixed solvent composition. The results are shown in Table 38.

                  TABLE 38                                                         ______________________________________                                         Portion of                                                                     fraction                                                                              Example 80:      Example 81:                                            collected                                                                             Composition (%)  Composition (%)                                        (%)    R225mix  R51-14  2-PrOH                                                                               R225mix                                                                               R51-14                                                                               2-PrOH                              ______________________________________                                         20     20.0     73.0    7.0   60.0   38.5  1.5                                 40     20.0     73.0    7.0   60.0   38.5  1.5                                 60     20.1     72.9    7.0   59.9   38.6  1.5                                 ______________________________________                                    

EXAMPLE 82

The same procedure as in Example 70 was repeated, except that 1,000 g of a mixed solvent composition consisting of 30% of R225mix (R225ca/R225cb=45%/55%), 46% of R51-14, 12% of R51-14my, 5% of R51-14mcy and 7% of 2-PrOH was used as a mixed solvent composition. The results are shown in Table 39.

                  TABLE 39                                                         ______________________________________                                         Portion of                                                                             Example 82:                                                            fraction                                                                               Composition (%)                                                        collected (%)                                                                          R225mix  R51-14  R51-14my                                                                               R51-14mcy                                                                              2-PrOH                                ______________________________________                                         20      30.0     46.0    12.0    5.0     7.0                                   40      30.0     46.0    12.0    5.0     7.0                                   60      29.9     46.1    12.0    5.0     7.0                                   ______________________________________                                    

EXAMPLE 83

The same procedure as in Example 70 was repeated, except that 1,000 g of a mixed solvent composition consisting of 50% of R225mix (R225ca/R225cb=45%/55%), 35% of R51-14, 9% of R51-14my, 4.5% of R51-14mcy and 1.5% of 2-PrOH was used as a mixed solvent composition. The results are shown in Table 40.

                  TABLE 40                                                         ______________________________________                                         Portion of                                                                             Example 83:                                                            fraction                                                                               Composition (%)                                                        collected (%)                                                                          R225mix  R51-14  R51-14my                                                                               R51-14mcy                                                                              2-PrOH                                ______________________________________                                         20      50.0     35.0    9.0     4.5     1.5                                   40      50.0     35.0    9.0     4.5     1.5                                   60      50.1     34.9    9.0     4.5     1.5                                   ______________________________________                                    

EXAMPLE 84

The same procedure as in Example 70 was repeated, except that 1,000 g of a mixed solvent composition consisting of 20% of R225mix (R225ca/R225cb=45%/55%), 75% of R51-14 and 5% of 2-PrOH was used as a mixed solvent composition. The results are shown in Table 41.

                  TABLE 41                                                         ______________________________________                                         Portion of                                                                               Example 84:                                                          fraction  Composition (%)                                                      collected (%)                                                                            R225mix       R51-14  2-PrOH                                         ______________________________________                                         20        20.0          75.0    5.0                                            40        20.0          75.0    5.0                                            60        20.1          74.9    5.0                                            ______________________________________                                    

EXAMPLE 85 to 98

By using the mixed solvent compositions shown in Table 42 (R225mix is a mixture of R225ca/R225cb=45%/55%), a machine oil cleaning test (A), a defluxing test (B) and a test (C) for removing deposited water were carried out. In Table 42, A, B and C indicate the degrees of removal A, B and C of the respective tests.

                                      TABLE 42                                     __________________________________________________________________________     Example                                                                             Solvent composition     %      A B C                                      __________________________________________________________________________     85   R225mix/R51-14/MeOH     45/45/10                                                                              ⊚                                                                 ⊚                                                                 ⊚                       86   R225mix/R51-14/MeOH     35/62/3                                                                               ⊚                                                                 ⊚                                                                 ⊚                       87   R225mix/R51-14/R51-14my/R51-14mcy/MeOH                                                                 40/36/10/4/10                                                                         ⊚                                                                 ⊚                                                                 ⊚                       88   R225mix/R51-14/R51-14my/R51-14mcy/MeOH                                                                 50/34/9/4/3                                                                           ⊚                                                                 ⊚                                                                 ⊚                       89   R225mix/R51-14/EtOH     45/47/8                                                                               ⊚                                                                 ⊚                                                                 ⊚                       90   R225mix/R51-14/EtOH     28/69/3                                                                               ⊚                                                                 ⊚                                                                 ⊚                       91   R225mix/R51-14/R51-14my/R51-14mcy/EtOH                                                                 30/45/12/5/8                                                                          ⊚                                                                 ⊚                                                                 ⊚                       92   R225mix/R51-14/R51-14my/R51-14mcy/EtOH                                                                 28/50/13/6/3                                                                          ⊚                                                                 ⊚                                                                 ⊚                       93   R225mix/R51-14/R51-14my/R51-14mcy/EtOH/2-PrOH                                                          30/45/12/5/6/2                                                                        ⊚                                                                 ⊚                                                                 ⊚                       94   R225mix/R51-14/R51-14my/R51-14mcy/EtOH/MeOH                                                            30/45/12/5/6/2                                                                        ⊚                                                                 ⊚                                                                 ⊚                       95   R225mix/R51-14/2-PrOH   20/73/7                                                                               ⊚                                                                 ⊚                                                                 ⊚                       96   R225mix/R51-14/2-PrOH   60/38.5/1.5                                                                           ⊚                                                                 ⊚                                                                 ⊚                       97   R225mix/R51-14/R51-14my/R51-14mcy/2-PrOH                                                               30/46/12/5/7                                                                          ⊚                                                                 ⊚                                                                 ⊚                       98   R225mix/R51-14/R51-14my/R51-14mcy/2-PrOH                                                               50/35/9/4.5/1.5                                                                       ⊚                                                                 ⊚                                                                 ⊚                       __________________________________________________________________________ 

We claim:
 1. A mixed solvent composition, which consists essentially of an azeotropic mixture consisting essentially of 52% by weight of 3,3-dichloro-1,1,1,2,2-pentafluoropropane and 48% by weight of 1,1,1,2,3,4,4,5,5,5-decafluoropentane.
 2. A mixed solvent composition, which is an azeotropic mixture consisting essentially of from 42% by weight of 1,3-dichloro-1,1,2,2,3-pentafluoropropane and 58% by weight of 1,1,1,2,3,4,4,5,5,5-decafluoropentane. 